This invention relates to novel 13alpha-alkylgonan-delta.sup.9(11) -5,10-epoxides and to a method for their preparation.
11beta-Aryl-substituted 13alpha-alkylgonans are known to be effective antigestagens and antiglucocorticoids (Steroids 44, 349 [1984], European Patent Application, Publication No. 0129 499).
In the process used up to now, their production takes place via an 11beta-aryl substituted 13alpha-alkyl-5alpha-hydroxy-17-oxo-gonan intermediate product. By nucleophilic addition of a side chain on the 17-ketone, optional variation of the C-17 substituent pattern, and then splitting off of water with simultaneous cleavage of the protecting groups present, the intermediate is converted in each case into the desired end product. A serious disadvantage of this process is the occurrence of nonstereoselective introduction of the C-17 side chain into the steroid skeleton. As a result, a yield-reducing and mostly very expensive separation of the two epimers becomes necessary.